Eating disorders are very prevalent both in the United States and worldwide. Though males can be and are affected, the disorders predominate in women, with staggering statistics. It is predicted that 0.5 to 3.7 percent of women suffer from anorexia nervosa at some point in their lives, with a 1.1 to 4.2 percent lifetime prevalence of bulimia nervosa on top of that statistic (National Association of Anorexia Nervosa and Associated Disorders). Eating disorders were reported to be the third most common illness classified as “chronic” for adolescents in 2000.

Recent studies have linked eating disorders to impaired cognitive functioning. Evidence points to problems with visuo-spatial reasoning and motor function. More important, the functioning of the central executive seems to be impaired in eating disordered patients (Weider et. al. 2014). The central executive is a critical component of the mind. It is, in a sense, the conductor, or boss, that coordinates thinking. Executive functions include the initiation of decision making, allocating attention, and planning out tasks.

Eating disorder patients often have persistent, obsessive thoughts about food, hunger, exercise, body shape and the like. It is possible that these thoughts “use up” some of their cognitive resources most of the time, leaving less ability to plan other decisions and perform other tasks. It is also possible that malnourishment also decreases their cognitive resources.

Let’s call this Theory 1: The link between eating disorders and decreased cognitive function comes from decreased cognitive resources caused by constant malnourishment and obsessive thinking about food, hunger, etc. If theory 1 is true, then cognitive function should return to normal levels if someone who had an eating disorder gets mentally and physically healthy.

Another possibility, call it Theory 2, is that diminished cognitive function is permanent and will not increase to normal levels even if someone gets mentally and physically healthy. This permanent impairment could be a pre-existing state or it could be caused by permanent damage as a result of malnourishment.

To distinguish between Theory 1 and Theory 2, Weider et al, (2014) tested patients and controls using a composite executive function score from such tasks as categorizing objects, sorting cards, inhibiting reading to identify colors and planning out the building of a tower. Anorexic patients performed about 1.5 standard deviations below healthy controls, whereas bulimics still performed below the healthy, at approximately 0.5 standard deviations below the mean control score. However, after adjusting for such factors as body mass index and depression score, which may be indicative of the patients current state of disorder, only a small improvement was made in approaching the healthy mean. Therefore, it seems that the current state of malnourishment cannot be the whole story.

Additional studies support this conclusion. A longitudinal study of executive function in eating disorders, conducted by Gillberg et al. (2010), tested subjects during adolescence, when they were afflicted by the disorder, and eighteen years later, when 84 percent of participants were found to be completely recovered. People who had suffered from an eating disorder performed more poorly than controls on this test 18 years later, even though these participants were now well-nourished and lacking a clinical diagnosis. Furthermore, in viewing the brain with MRI and fMRI to understand its structure and activity, eating disorder patients’ brains revealed various abnormalities including altered blood flow to the temporal lobes, decreased grey matter, and more. Some problems improved after the patient regained weight, indicating a malnourishment component, but some did not (Lena, 2004).

Together, these results support Theory 2. People with eating disorders did not fully recover even after they were healthy.

Debate continues about why. It is possible that being malnourished damaged the brains of people with eating disorders. Alternatively, these deficits in abilities might have been present before the onset of the disorder. It is difficult to distinguish between pre-existing differences and effects of brain damage. Given the prevalence of eating disorders, continued exploration of this question is critical.

One thing is clear: People with eating disorders often have mild cognitive impairments. These impairments can have far-reaching consequences (including increased likelihood of relapse following treatment; Duchesne et al., 2004). And they do not necessarily go away when these patients get healthy. Acknowledging these impairments can promote better understanding of the victims of eating disorders, and hopefully result in better treatment and recovery for all involved.

Theory 3 would be that cognitive function returns to normal if the sufferer from anorexia nervosa is returned to normal weight within a reasonable period of time, but if the state of semi-starvation persists for a long period (the best available evidence indicates more than three years) then the changes in the brain become relatively permanent and very difficult to reverse.

Also, it is important to remember than many of the cognitive differences associated with anorexia include superior ability, compared to the general population, in some respects including, for example, local processing, as distinguished from global processing. Lang,
Central Coherence in Eating Disorders, http://www.ncbi.nlm.nih.gov/pubmed/24882144 In other words, some of the traits associated with some people with anorexia nervosa are positive. Those traits allow these people to accomplish some tasks more efficiently than most people can, and often cause them to become very successful and happy in life, after they have been returned to a health weight and resume normal patterns of eating.

If only there was as much focus on over eating as under eating in the psychology world. A staggering 30% of women are obese, that makes anorexia seem like a rather small problem yet it seems to get a majority of the "eating disorder" press and far more "credit" as a societal problem then being grossly fat.

I'm not sure I understand what is meant by "grossly fat." That seems to be a value statement, not a scientific term.

Also, I think it's hard to argue that anorexia nervosa gets more "focus" than "obesity." The annual budget in the U.S. for anorexia nervosa research is approximately $11 million. By contrast, the annual research budget devoted to obesity is more than $800 million. These figures can be confirmed on the website of the National Institutes of Health. Thus, for purposes of scientific research, obesity receives a "focus" that is about eighty times greater than anorexia nervosa. Sadly, this is true even though anorexia nervosa is one of the leading causes of death and disability in young people.

Obesity and weight loss topics are everywhere. Weight loss is an obsession within our western culture. I would actually wager that REDS (restrictive eating disorders) generate much less attention than the "Obesity Epidemic" (research will provide insight into how this isn't a 100% fact).

It's important not to jump to conclusions on the basis of the Weider and Gillberg papers, because the results they reported have not been consistently replicated. Replication is a key aspect of good scientific research.

Moreover, a different study, by Billingsley-Marshall (2013), found that only a minority (30%) of eating disorder sufferers showed evidence of any impaired executive function. http://www.ncbi.nlm.nih.gov/pubmed/23354876 In the Billingsley-Marshall study, the impairment was more strongly correlated with levels of anxiety than with eating disorder symptoms. The people in the study were treated for their eating disorder in a psychiatric hospital setting, an environment that will actually tend to cause anxiety. Consequently, it is possible that the "treatment" for the eating disorder -- hospitalization -- was what was indirectly causing the difficulties with executive function by causing the sufferer to become anxious. Disentangling the effects of "treatment" from the effects of the eating disorder, therefore, would be necessary in order to find any association between the eating disorder and executive function.

There exist an enormity of confounding variables that must be acknowledged and accounted for before drawing such conclusions, particularly the high incidence of co-morbidities that in themselves negatively impact executive and overall cognitive functions, such as anxiety and depression. A longitudinal study to consider such function before and after periods of severe intake reduction would greatly aid exploration of this topic, yet this would of course be hard to construct! (Perhaps it could be arranged for inpatients of disordered eating clinics, and correlated to whether or not these patients maintain normal or return to disordered eating habits following discharge.) I also agree with the previous commenter that the overall duration and severity of malnourishment must also be considered.

Whilst here, I must ask: was this somebody's undergraduate college assignment? The clunky sentences, awkward style, and overall poor readability sadly let down this otherwise very interesting topic; some editorial guidance would not have gone astray.

This essay WAS written by an undergraduate. And she did a fabulous job. In my opinion it is well written and clear. (Also, I edited it and so whatever flaws it has are just as much my responsibility as hers.) I'm proud to have had her in my class and I know she will continue to do great things.

Dear Mr. Kornell,
You write in this article that "Acknowledging these impairments can promote better understanding of the victims of eating disorders." How? My experience is the opposite. It is my observation that your approach leads to stereotyping and prejudice. For what it's worth, my kid had AN as a teenager and she wasn't cognitively impaired. All the clinicians assumed she was, and that mindset played a role in their inability to effectively treat the anorexia nervosa. When my wife and I discovered Family Based Treatment (also known as FBT or "Maudsley") we, as parents, took control away from the professionals who treated my kid not as a unique individual but as a stereotype. Our kid then recovered well. She remains completely recovered now, many years later. My experience, and my reading of the research literature, has convinced me, therefore, that it is counterproductive and harmful to treat sufferers from anorexia nervosa as if they were cognitively impaired.

Depending on the severity of the ED there will undoubtedly be cognitive impairment at the time and likely onwards into treatment. Self-starvation in and of itself is a cognitive issue, it is an irrational fear response to food. I am a recovering AN, and believe that during starvation and even post-starvation cognition as it relates to food/exercise is still less than perfect or normal.

Eating more food and restoring weight are the best and only known cures for the cognitive deficits associated with anorexia nervosa.
See Lozano-Serra, Adolescent Anorexia Nervosa: Cognitive Performance After Weight Restoration,http://www.ncbi.nlm.nih.gov/pubmed/24360134

I understood that anorexia was, inter alia, a sub-concious attempt to "Stop all the clocks",the line from Auden's poem about the death of a loved one; that people who didn't want change (students unable to decide on a career, older people facing lonliness after death of a loved one, etc.) subconsciously stopped eating - eating being associated with growing up and moving on and lack of eating being associated with not growing up not moving on (children told 'eat your food so that you will grow up to be a big boy, girl - thus the subconscious link)